A dual clutch type transmission (a twin clutch type transmission) having two clutches is disclosed in JP2007-232047A, for example. In the dual clutch type transmission, rotation of an output shaft of an engine is transmitted to one of first and second input shafts of a transmission by means of one of first and second clutches of a dual clutch, and then rotational speed of the first and second input shafts is changed by means of each shift stage gear set, arranged between each of the first and second input shafts and an output shaft of the transmission, before the rotation is transmitted to the output shaft. The dual clutch type transmission includes a function for switching between an automatic speed change mode and a manual speed change mode. In the automatic speed change mode, an upshift/downshift command is automatically outputted by executing a program stored in a microcomputer in order to establish an appropriate shift stage. In the manual speed change mode, a shift command is outputted in response to a manual operation of a driver in order to establish a desired shift stage.
In the automatic speed change mode of the dual clutch transmission according to JP2007-232047A, a next shift stage is determined on the basis of an operation amount of an accelerator, detected by means of an accelerator position sensor, and a vehicle speed, detected by an output shaft sensor, and then one of the shift stage gear sets between an input shaft, which is not transmitting rotational torque, and an output shaft is selected to be in a standby state of the determined next shift stage (a pre-shift control). Consequently, a shift operation during the automatic speed change mode is executed quickly. Further, in the manual speed change mode, external information, such as a radius of curvature of a road, is obtained from a navigation control apparatus, so that a next shift stage is determined on the basis of the obtained external information and the vehicle speed, detected by the output shaft sensor, and thereby the pre-shift control is executed in the same manner as the automatic speed change mode.
According to the dual clutch type transmission disclosed in JP2007-232047A, in the automatic speed change mode, the pre-shift control of a next shift stage is executed by means of the microcomputer which controls shifting to the next shift stage. Therefore, the pre-shift control is surely executed before the shift stages are shifted. In the manual speed change mode, however, the pre-shift control is executed on the basis of the external information of roads and the like, obtained from the navigation control apparatus. Therefore, whether the driver has the intention of accelerating the vehicle speed or decelerating the vehicle speed may not be determined only on the basis of the external information. Accordingly, when the shift command is outputted in response to an operation of the driver, the shift stages may be shifted subsequently so as to form a corresponding shift stage, and then, the dual clutch may be shifted in order to complete the shift operation. As a result, the driver may feel uncomfortable because a time required for shifting to the desired shift stages is increased.
A need thus exists for a dual clutch transmission, which is not susceptible to the drawback mentioned above.